Trichomonas vaginalis is the causative agent of trichomoniasis,one of the most common sexually transmitted infections. Trichomoniasis can be treated with the antibiotic metronidazole, but the number of strains resistant to this drug is increasing. Regulationof gene expression has been implicatedas the drivingforce behind T.vaginalis drug resistance. In order to better understand the transcriptionalcharacteristics involved in drug resistance and other pathogenic traits it is important to study the basic regulation of gene expression in T.vaginalis. Gene expression is primarily controlled by core promoter elements. Aim 1 seeks to identify and characterize novel and evolutionarily conserved core promoter motifs. "Novel motifs can lead to novel DNA binding proteins, which can serve as potential chemotherapeutic targets. To date, all characterized genes in T.vaginalis are solely regulated by the initiator (Inr)core promoter element. The novel initiator binding protein, IBP39 binds specifically to the Inr element. Aim 2 will identify other nuclear proteins that interact with IBP39 to form a transcription pre-initiation complex. To further characterize gene expression in T. vaginalis an in vitro transcription system will be developed in Aim3. This system will be employed to explore the requirementsof core promoter motifs and proteins in transcription. In general, the results of this study will enhance our understandingof gene expression in T. vaginalis, which may lead to additional treatments of trichomoniasis.